(a) Technical Field
The present invention relates to a filter switching device for a fluorescence endoscopic television camera system. More particularly, it relates to a filter switching device for a fluorescence endoscopic television camera system, which selectively transmits light to a detector sensor of a television camera according to the white light condition or the fluorescence condition to diagnose patients using a fluorescence endoscope.
(b) Background Art
Generally, a fluorescence endoscope has been used for the diagnosis of various diseases. The fluorescence endoscope enables the fluorescence observation of a target part of the body by irradiating excitation light on the target part while performing the functions of a typical endoscope for observing the surface of the internal parts of the body in detail.
For the diagnosis of patients using the fluorescence endoscope, a general reflection white light image reflected by the target part under the white light condition and a fluorescence image generated by the excitation light irradiated from the target part under the fluorescence condition are needed.
For this, a television camera with a high sensitive color chip is provided on the typical fluorescence endoscope so as to perform white light observation and fluorescence observation on the target part.
The television camera is provided with a detector sensor that is installed at one side of the television camera to implement the fluorescence image. The detector sensor of the television camera is connected to the fluorescence endoscope via a camera head so as to detect signal light delivered through the fluorescence endoscope.
In this case, the signal light incident under the white light condition and the fluorescence condition needs to be located on a signal light path before entering the detector sensor of the television camera such that light can be selectively transmitted to the detector sensor according to the white light condition and the fluorescence condition. Accordingly, a filter switching device needs to be provided in the camera head.
The television camera head connected to the external endoscope needs to have a small size, and have a sealed structure to maintain autoclaving. Also, the television camera head needs to have an ergonomic design and provide convenience for use.
Therefore, a filter switching device that can be installed in the camera head with a sealed structure and can conveniently replace a filter according to the while light or fluorescence condition upon diagnosis is needed.
Meanwhile, there are many prior documents about devices for moving optical parts in a camera head.
U.S. Pat. No. 6,932,760 discloses an autoclavable coupler for an endoscopic camera system. In this patent, when a focusing ring located outside a lens rider rotates, the rotating movement is changed into the straight movement by a screw and a groove located inside, and a lens holder with a lens is configured to move forward and backward between an endoscope and a CCD camera while being sealed.
Also, U.S. Pat. No. 5,056,902 discloses a magnetically coupled lens actuator. Unlike U.S. Pat. No. 6,932,760 described above, this patent is characterized in that a coupler is configured with a magnetic factor instead of a mechanical factor. That is, when an outermost tube rotates, a sleeve therein rotates to cause the rotating movement to be changed into the straight movement by a screw and a groove and cause the tube to move together with the movement of a cylindrical magnetic substance.
However, both above-mentioned patents are configured to allow a lens to move forward and backward in a sealed body to adjust the focus of the lens, and are not suitable for a filter switching device that needs a movement mechanism in which a filter can be located on the optical path and then be removed.
That is, both patents were developed such that lenses move forward and backward along the optical axis of the camera head in a sealed space using external rotating movement, while the optical filters need to be moved in a direction orthogonal to the optical axis to selectively implement the fluorescence and white light conditions. Accordingly, a device suitable for the filter replacement is needed.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.